1. Field of the Invention
This invention relates to an electro-strictive actuator, particularly to a structure to connect an electro-strictive element to its mechanical load.
2. Description of the Related Arts
In a printer head of a wire-dot printer, an electro-strictive element has been recently employed for actuating an impact printing wire in order to satisfy the recent trend aiming at a higher printing speed.
In a prior art structure shown in FIG. 1 to structurally connect an electro-strictive element 2 to a metal block 7 to output a mechanical displacement caused from an electro-strictive phenomena, i.e. an expansion, of the electro-strictive element 2 to the impact printing wire, block 7 is adhered to electro-strictive element 2 by an adhesive 13a placed between a flat surface 7a of block 7 and a flat surface 2a of electro-strictive element 2, as well as by another adhesive 13b to adhere sides of electro-strictive element 2 to flat surface 7a of block 7. The mechanical displacement, i.e. mechanical output, of the electro-strictive element is typically as small as 15 .mu.m. Adhesive 13a between two surfaces 2a and 7a is formed of an approximately 50 .mu.m thick resin. There is a problem with the prior art structure in that the adhesive 13a, which is softer than metals and is located between metal block 7 and the electro-strictive element 2, attenuates the propagation of the displacement output from electro-strictive element 2, resulting in a decrease in the mechanical output. If the thickness of the adhesive member is reduced, the adhesion strength is reduced.